Environment arrangement robot and control program thereof

ABSTRACT

An environment arrangement robot includes a map creation unit that divides the target space into a plurality of cell spaces and provides an evaluation value to each of the cell spaces, in which the evaluation value indicates a probability of whether or not there is an object in the corresponding cell space, and an environment change unit that changes, among the plurality of cell spaces, a specific cell space having the evaluation value within a range evaluated that the probability of whether or not there is an object in the specific cell is low in such a way that the probability that the object is present will become greater or change a surrounding cell space in such a way that the specific cell space will be excluded from the measurement by the distance sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2017-88871, filed on Apr. 27, 2017, thedisclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

The present disclosure relates to an environment arrangement robot and acontrol program thereof.

There is known a technique in which a mobile robot moving autonomouslycreates and updates an environment map while calculating its ownlocation together with its reliability (see, for example, JapaneseUnexamined Patent Application Publication No. 2014-203145).

SUMMARY

When the autonomous mobile robot autonomously moves while estimating itsown location with reference to the created environment map, if there isa part of the environment map with low reliability, the mobile robotsometimes cannot accurately recognize the current location and thusunable to reach a destination.

The present disclosure has been made to solve such a problem. Thepresent disclosure provides an environment arrangement robot thatcreates an environment map of a target space in which a mobile robotautonomously moves and also arranges an environment of the target spaceso that the mobile robot can accurately estimate its own location.

A first example aspect of the present disclosure is an environmentarrangement robot for arranging an environment of a target space inwhich a mobile robot autonomously moves. The environment arrangementrobot includes: a movement mechanism for autonomous movement; a distancesensor configured to measure a distance to an object present nearby; amap creation unit configured to divide the target space into a pluralityof cell spaces and provide an evaluation value to each of the cellspaces based on a result of the measurement of the distance sensorobtained while the environment arrangement robot autonomously moves inthe target space to thereby create an environment map of the targetspace, the evaluation value indicating a probability of whether or notthere is an object in the corresponding cell space; and an environmentchange unit configured to change, among the plurality of cell spaces, aspecific cell space having the evaluation value within a range evaluatedthat the probability of whether or not there is an object in thespecific cell space is low in such a way that the probability that theobject is present will become greater or change a surrounding cell spacein such a way that the specific cell space will be excluded from themeasurement by the distance sensor.

When the target space is arranged by such an environment arrangementrobot, the autonomous mobile robot that autonomously moves later on caneasily recognize the target space, and by referring to the environmentmap created by the environment arrangement robot, the autonomousmovement robot can estimate its own location more accurately.Consequently, the autonomous mobile robot can reach a destination morereliably.

Further, in the above-described environment arrangement robot, the mapcreation unit may update the evaluation value of the specific cell spaceand the evaluation value of a cell near the specific cell space changedby the environment change unit based on a remeasurement result of thedistance sensor. By reevaluating the space thus arranged, it is possibleto create the latest environment map. The environment arrangement robotmay further include a transmission unit configured to transmit theenvironment map created by the map creation unit to the mobile robotthat autonomously moves in the target space later on. If the environmentmap can be shared as soon as possible, efficiency of works carried outby mobile robots improves.

The above-mentioned environment map may be a map of one horizontal crosssection of the target space. The main purpose of using the environmentmap created by the environment arrangement robot is to estimate alocation of the autonomous movement robot. Thus, the environment map mayinclude surrounding information to enable the autonomous mobile robot toestimate its own location. By limiting the map created in this way toone horizontal section of the target space, the environment arrangementrobot can quickly create the environment map.

Moreover, the environment change unit may attempt to attach apredetermined attaching object to the specific cell space or to disposematerials for shielding the specific cell space. For example, when anopaque attaching object is attached to a transparent glass door, thedistance sensor can easily recognize the glass door, and thus theprobability of whether or not there is an object in the specific cellspace is improved. When the materials are placed in the surrounding cellspace to shield the specific cell space, the autonomous mobile robotmoving in the target space later on does not need to evaluate as towhether or not there is an object in the specific cell space. Thisenables the autonomous mobile robot to estimate its own location moreaccurately.

Further, when the environment arrangement robot includes a notificationunit configured to notify, when the change of the cell space targeted bythe environment change unit fails, a user of the failure, the user canchange the environment by himself/herself. Even when the environmentarrangement robot cannot change the environment, if the user changes theenvironment, the autonomous mobile robot that autonomously moves lateron can easily recognize the target space.

After the map creation unit creates the environment map until apredetermined condition is satisfied, the environment arrangement robotmoves to near the specific cell space, and the environment change unitexecutes the change of the cell space to be the target. For example,when the same cell space is measured several times in accordance withthe predetermined condition, it is possible to reduce the influence of amoving object accidentally present in the cell space on the evaluationvalue.

A second example aspect of the present disclosure is a control programof an environment arrangement robot for arranging an environment of atarget space in which a mobile robot autonomously moves. The controlprogram causes a computer to execute: measuring, by a distance sensor, adistance to an object present nearby while operating a movementmechanism and the environment arrangement robot autonomously moves inthe target space; dividing the target space into a plurality of cellspaces and providing an evaluation value to each of the cell spacesbased on a result of the measurement of the distance sensor obtained inthe measuring to thereby create an environment map of the target space,the evaluation value indicating a probability of whether or not there isan object in the corresponding cell space; and changing, among theplurality of cell spaces, a specific cell space having the evaluationvalue within a range evaluated that the probability of whether or notthere is an object in the specific cell is low in such a way that theprobability that the object is present will become greater or change asurrounding cell space in such a way that the specific cell space willbe excluded from the measurement by the distance sensor.

When the environment arrangement robot is operated by such a controlprogram, the target space is arranged, and the autonomous mobile robotthat autonomously moves later on can easily recognize the target space.By referring to the environment map created by the environmentarrangement robot, the autonomous mobile robot can estimate its ownlocation more accurately. Consequently, the autonomous mobile robot canreach a destination more reliably.

The environment arrangement robot according to the present disclosurecreates an environment map of a target space in which a mobile robotautonomously moves and also arranges an environment of the target space.Thus, later on, the mobile robot can estimate its own location moreaccurately.

The above and other objects, features and advantages of the presentdisclosure will become more fully understood from the detaileddescription given hereinbelow and the accompanying drawings which aregiven by way of illustration only, and thus are not to be considered aslimiting the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an external perspective view of an environment arrangementrobot according to an embodiment;

FIG. 2 is a control block diagram of the environment arrangement robot;

FIG. 3 is a diagram illustrating a state of distance measurement using adistance sensor;

FIG. 4 is a diagram showing an example of a target space and a spacesearch for creating an environment map;

FIG. 5 is a diagram for describing the environment map created by thespace search;

FIG. 6 is an external perspective view of the environment arrangementrobot that transports shielding materials;

FIG. 7 is a diagram showing a target space in which a specific cellspace is shielded by shielding materials;

FIG. 8 is a diagram for describing the environment map created after theenvironment is changed; and

FIG. 9 is a flowchart illustrating a processing flow of the environmentarrangement robot.

DESCRIPTION OF EMBODIMENTS

Hereinafter, although the present disclosure will be described withreference to embodiments of the present disclosure, the presentdisclosure according to claims is not limited to the followingembodiment. Moreover, all the components described in the followingembodiment are not necessarily indispensable for means to solveproblems.

FIG. 1 is an external perspective view of an environment arrangementrobot 100 according to this embodiment. The environment arrangementrobot 100 is roughly divided into a cart part 110 and an arm part 120.

The cart part 110 is mainly composed of a base 111, two driving wheels112 attached to the base 111, and one caster 113. The two driving wheels112 are disposed so that rotational axes thereof coincide on oppositelateral sides of the base 111. Each of the driving wheels 112 is rotatedindependently by a motor (not shown). The caster 113 is a trailingwheel. The caster 113 is disposed in such a way that a pivot shaftextending from the base 111 in the vertical direction pivotally supportsthe wheel away from a rotation axis of the wheel. The caster 113 followsthe cart part 110 in a direction in which the cart part 110 moves. Forexample, the environment arrangement robot 100 moves straight if the twodriving wheels 112 are rotated at the same rotation speed in the samedirection, while it turns around a vertical axis passing through acenter of gravity thereof if the two driving wheels 112 are rotated atthe same rotation speed in the directions opposite to each other.

Various sensors for detecting obstacles and for recognizing asurrounding environment are provided on the cart part 110. The cameras114 are one of the sensors. Two of the cameras 114 are disposed on thefront side of the base 111. The cameras 114 each include, for example, aCMOS image sensor. The cameras 114 transmit captured image signals to acontrol unit, which will be described later. A distance sensor 115 isfurther disposed on the front side of the base 111. The distance sensor115 is a sensor that measures a distance to an object present nearby.The distance sensor 115 according to this embodiment is a rider thatmeasures the distance to a projection point by projecting a laser beamwhile scanning it in the horizontal cross section direction anddetecting reflected light. The details will be described later.

A control unit 190 is provided in the cart part 110. The control unit190 includes a control unit, a memory, and the like, which will bedescribed later.

The arm part 120 is mainly composed of a plurality of arms 121, 122, and123 and a hand 124. One end of the arm 121 is rotatably supported by thebase 111 in such a way that the arm 121 is rotatable around the verticalaxis. One end of the arm 122 is rotatably supported by the other end ofthe arm 121 in such a way that the arm 122 is rotatable around ahorizontal axis. One end of the arm 123 is rotatably supported by theother end of the arm 122 in such a way that the arm 123 is rotatable ina radial direction at the other end of the arm 122. The hand 124 isrotatably supported by the other end of the arm 123 in such a way thatthe hand 124 is rotatable around a central axis parallel to a directionin which the arm 123 is extended.

The hand 124 includes a holding mechanism so as to be able to hold aconveying object such as a shielding material for the environmentarrangement robot 100, which will be described later. The environmentarrangement robot 100 is not limited to conveying the conveying objectbut instead can be employed for various purposes. The arm part 120 holdsvarious workpieces according to a task given to the environmentarrangement robot 100.

FIG. 2 is a control block diagram of the environment arrangement robot100. The control unit 200 is, for example, a CPU. The system controlunit 200 transmits and receives information such as commands, samplingdata, and the like to and from a driving wheel unit 210, an arm unit220, a sensor unit 230, a memory 240, a transmission unit 250, anotification unit 260, and the like, whereby the control unit 200executes various calculation related to control of the mobile robot 10.

The driving wheel unit 210 is provided in the cart part 110. The drivingwheel unit 210 includes a driving circuit and a motor for driving thedriving wheels 112, an encoder for detecting an amount of rotation ofthe motor, and the like. The driving wheel unit 210 functions as amovement mechanism for autonomous movement. The control unit 200transmits a driving signal to the driving wheel unit 210 to therebyexecute rotation control of the motor. Further, the control unit 200receives a detection signal of the encoder to thereby calculate a movingspeed, a moving distance, a turning angle, and the like of theenvironment arrangement robot 100.

The arm unit 220 is provided in the arm part 120. The arm unit 220includes a driving circuit for driving the arms 121, 122, and 123 andthe hand 124, an actuator, an encoder for detecting an operation amountof the actuator, and the like. The control unit 200 transmits a drivingsignal to the arm unit 220 to thereby operate the actuator and executeposture control and hold control of the arm part 120. The control unit200 receives the detection signal of the encoder to thereby calculate anoperating speed, an operating distance, a posture and the like of thearm part 120.

The sensor unit 230 includes various sensors in addition to the cameras114 and the distance sensor 115. These sensors are dispersedly disposedon the cart part 110 and the arm part 120. The control unit 200transmits a control signal to each sensor to thereby obtain its output.For example, the cameras 114 execute a capture operation in accordancewith the control signal from the control unit 200 and transmit capturedframe image data to the control unit 200. Moreover, the distance sensor115 transmits, in accordance with a request signal from the control unit200, a projection direction of the laser beam and a distance from areference position to a target to the control unit.

The memory 240 is a non-volatile storage medium. For example, a solidstate drive is used as the memory 240. The memory 240 stores a controlprogram for controlling the environment arrangement robot 100, variousparameter values, functions, lookup tables, and the like used forcontrol. In particular, the memory 240 includes a storage area for a mapDB 241. The map DB 241 is a database in which various pieces of mapinformation for autonomous movement are described.

The transmission unit 250 transmits various pieces of information andcontrol signals to external devices and other autonomous mobile robotsunder the control of the control unit 200. The transmission unit 250 is,for example, a wireless LAN unit. It is obvious that the transmissionunit 250 may include a function as a reception unit. In this embodiment,the transmission unit 250 is responsible for transmitting the createdenvironment map to other autonomous mobile robots.

The notification unit 260 is responsible for notifying a user of a stateof the environment arrangement robot 100 and surrounding circumstances.The notification unit 260 is, for example, a speaker or a display panel.The notification unit 260 notifies the user of contents to betransmitted to the user by using voice, characters, and videos. Thenotification unit 260 may be a transmission unit that transmits thenotification contents to a terminal device carried by a user. In thiscase, the transmission unit 250 may include the function of thenotification unit 260.

The control unit 200 also functions as a function execution unit thatexecutes various calculations related to the control and execute thecontrol. The map creation unit 201 executes the control program. Thecontrol program operates the distance sensor while searching the targetspace, calculates an evaluation value indicating the probability ofpresence/absence of an object, and creates the environment map. Further,when there is a space where it is uncertain whether the object ispresent or not in the target space, an environment change unit 202executes a control program for changing the environment. Details will bedescribed later.

FIG. 3 is a diagram for describing a state of distance measurement usingthe distance sensor 115. The distance sensor 115, which is a rider,projects the laser beam in a horizontal cross section direction at aheight h from a floor surface. To be more specific, for example,micromirrors are driven to scan the laser beam in a range of about 180degrees in front of the base 111. Then, reflected light with respect tothe scanned projected light is detected to thereby calculate thedistance to a reflection point.

The distance sensor 115 can detect the distance from a laser projectionunit, which is a reference point, to the object if the object is presentwithin the distance L₀. That is, a detection area is a forward range ofabout 180 degrees and a radius L₀ around the reference point. As shownin FIG. 3, when an object 601 is present within the detection area,detection points at which the distances thereof have been measuredappear continuously on the surface of the object 601 in a straight line(bold lines in FIG. 3). At this time, the distance sensor 115 outputsthe projection direction of the laser and the distance from thereference point for each detection point. The projection direction ofthe laser is, for example, an angle formed by the laser with respect tothe front direction. In the illustrated example of the detection points,the distance is L_(x) and the projection direction is θ_(x). When thedistance sensor 115 cannot detect the object within the range of thedistance L₀, it outputs a result indicating that there is no detectedobject.

The distance sensor 115 outputs a verification value indicating theprobability of the detection result in addition to the projectiondirection of the laser and the distance from the reference point. Forexample, when intensity of the reflected light is large, a large valueis given to the verification value indicating that the distance isaccurately detected. Conversely, when the intensity of the reflectedlight is small, a small value is given to the verification valueindicating that the distance is uncertain. When a method of performingscans a plurality of times and outputting the detection results isadopted, and if variations in the respective detection results aresmall, a large value is given to the verification value. Conversely,when the variations in the respective detection results are large, asmall value is given to the verification value.

Specifically, for example, when laser is projected on a transparentglass, as the reflectance on the surface of the transparent glass islow, the intensity of the reflected light to be detected is low. Inaddition, when the surface of the object is vibrating or a material ofthe object absorbs laser beams, the detection result varies or theintensity of the reflected light becomes low. That is, the detectedresult may become uncertain depending on the state or material of thesurface of the object irradiated with the laser beam. In such a case, asmall value is given to the verification value.

In this embodiment, the environment arrangement robot 100 creates theenvironment map of the target space based on the output of the distancesensor 115. The environment map to be created divides the target spaceinto a plurality of cell spaces. The evaluation value indicating theprobability of whether or not there is an object occupying at least apart of the corresponding cell space is given to each of the cellspaces. The evaluation value to be given to each cell space iscalculated based on the output of the distance sensor 115, which hasbeen obtained while the environment arrangement robot 100 autonomouslymoves around the target space. Note that the target space of thisembodiment is a space of a horizontal cross section at the height h fromthe floor surface, which is measured by the distance sensor 115.

The created environment map is used later on when the autonomous mobilerobot, which autonomously moves in the target space and executes taskssuch as works, performs calculation for self-location estimation inwhich the autonomous movement robot estimates its own location in thetarget space. More specifically, the autonomous mobile robot canrecognize where the autonomous mobile robot is located in theenvironment by checking the output obtained by its own distance sensor115 against the environment map received from the environmentarrangement robot 100. That is, prior to the mobile robot executing thetask in the target space, the environment arrangement robot 100 plays arole of searching the space, creating the environment map, and handingit over to the mobile robot. When the environment arrangement robot 100also plays a role of executing the task, it may execute the task whileestimating its own location using the environment map created by theenvironment arrangement robot 100 itself.

A specific procedure for creating the environment map will be described.The map creation unit 201 executes the control program for creating theenvironment map to create the environment map. FIG. 4 is a diagramshowing an example of the target space for creating the environment mapand the space search. As described above, the target space is the spaceof the horizontal cross section at the height h from the floor surfaceon which the distance sensor 115 is disposed. FIG. 4 is a schematicdiagram overviewing the entire environment including a target area 600in which the environment arrangement robot 100 moves around.

The target area 600 for which the environment map is to be created is aroom adjacent to a passage area 610. The entire target area 600 issurrounded by a wall 611, and a part facing the passage area 610 is anentrance 612 that allows the environment arrangement robot 100 to passbetween the passage area 610 and the entrance 612. A part of the wall611 is composed of a transparent glass door 613. There are a pluralityof pillars 614 in the target area 600. In addition, a plurality ofshelves 615 are installed. A person 690 occasionally performs works inthe target area 600. In the passage area 610, shielding materials 650,which will be described later, are stored side by side.

The environment arrangement robot 100 autonomously moves while finding apath through which the environment arrangement robot 100 can pass. Theenvironment arrangement robot 100 evaluates whether or not it can passthrough the path by obtaining outputs of sensors such as the cameras 114and the like and determining whether or not there is an obstacle in atraveling direction. It is obvious that the environment arrangementrobot 100 may refer to the output of the distance sensor 115 to make theevaluation.

The environment arrangement robot 100 monitors the driving wheel unit210 and executes autonomous movement while recognizing its own locationby dead reckoning. For example, the environment arrangement robot 100moves everywhere as thoroughly as possible along a path P inside thetarget area 600 shown in FIG. 4. In parallel to the moving of theenvironment arrangement robot 100, the environment arrangement robot 100stops in spots along the path P to operate the distance sensor 115 anddetects as to whether or not there is an object in the hatched range ofFIG. 3 with respect to the traveling direction. More specifically, theenvironment arrangement robot 100 obtains the position of the referencepoint at the time of sensing, the projection direction of the laserbeam, the distance to the detected target, and the verification value ofthe detected target. Then, the environment arrangement robot 100calculates the probability that the target is present and the cell spaceof the target area 600 in which the target is present.

FIG. 5 is a diagram for describing the environment map created throughthe space search as described above. The target area 600 is defined as aset of cell spaces divided into m×n in one layer including thehorizontal cross section at the height h from the floor surface.

The map creation unit 201 evaluates that there is no object in the cellspace through which the laser beam projected by the distance sensor 115has passed whereas it evaluates that there is an object in the cellspace where the laser beam is reflected. Further, it is assumed that thepresence/absence of the object cannot be confirmed in the cell space farfrom the cell space where the laser beam is reflected. The map creationunit 201 evaluates the cell space through which the laser beam haspassed and the cell space in which the laser beam is reflected based onthe position of the reference point at the time of sensing, theprojection direction of the laser beam, and the distance to the detectedobject. When the distance sensor 115 does not detect the object, thecell space included within the range of L₀, which is the detectabledistance from the reference point, is evaluated to be the cell space inwhich the object is not present.

Further, as described above, since the verification value is included ina result of the sensing, the map creation unit 201 calculates theevaluation value of each cell space based on the verification value. Theevaluation value is a value indicating the probability of whether or notthere is an object occupying at least a part of the corresponding cellspace for each of the cell spaces.

For example, when the evaluation value is any value from 0 or greaterand 1 or less, and “0” indicates “no object is present” and “1”indicates that “an object is present”, an intermediate value of “0.5”means that “presence/absence of an object is unknown”. Therefore, thecloser the value is to “0”, the more certain it is that “no object ispresent”, while the closer the value is to “1”, the more certain it isthat “object is present”. Conversely, the closer the value it is to theintermediate value of “0.5”, the more it can be said that“presence/absence of an object is unknown”.

The verification value indicating the probability of the detectionresult is a small value when, for example, a transparent glass isdetected as in the case above. In other words, the verification valuecan be regarded as representing the probability that the object ispresent at the detection point. Therefore, when the verification valueis large, the evaluation values close to “1” may be given to the cellspaces including the detection points, and the evaluation values closeto “0” can be given to the cell spaces therebetween. Conversely, whenthe verification value is small, the evaluation values close to “0.5”may be given to both the cell spaces including the detection points andthe cell spaces therebetween. That is, the map creation unit 201 canconvert the verification value output by the sensing into the evaluationvalue given to each cell space by using a predetermined conversionformula.

In addition, due to the autonomous movement of the environmentarrangement robot 100, the distance sensor 115 may project the laserbeams many times in the same cell space. In such a case, the evaluationvalue of the related cell space may be updated according to thedetection result. For example, the map creation unit 201 can set anaverage value of the previously calculated evaluation value and thenewly calculated evaluation value as the latest evaluation value.

Each cell space shown in FIG. 5 has the evaluation value calculated inthis way. The cell spaces having the evaluation values close to “0” areshown in white, and the cell spaces having the evaluation value close to“1” are hatched. Further, the cell spaces having the evaluation valuesclose to “0.5” are shown in dots, and the cell space in which thepresence or absence of an object cannot be confirmed are shown in black.Some of the lower left cell spaces are enlarged to show specific numericvalues given to the respective cell spaces.

As shown in FIG. 4, as there is the glass door 613 at the lower leftcorner, each of the evaluation value of the cell space corresponding tothe glass door 613 is a value close to “0.5”. On the other hand, theevaluation values of the cell spaces corresponding to the pillars 614are values close to “1”, indicating that the object is present at thesepositions more reliably. As shown in FIG. 4, although the person 690 asa moving object is temporarily present at the upper left of the targetarea 600, by performing the sensing over and over along the path P, theinfluence of the person 690 is successfully reduced. That is, even whenthere is a moving object at a certain point, if it moves afterwards, itis possible to reduce the influence of the moving object by performingthe sensing a plurality of times at different times and angles.

As described above, the environment map is used later on for theself-position estimation of the mobile robot that autonomously moves.However, when there is a cell space (referred to as a “specific cellspace”) having the evaluation value close to “0.5”, any result of thesensing in the cell space obtained by the mobile robot will not be amaterial for the evaluation of the self-location estimation. Theautonomous mobile robot sometimes cannot accurately recognize thecurrent location and unable to reach the destination. Therefore, theenvironment arrangement robot 100 of this embodiment changes theenvironment so that the specific cell space is physically shielded andis excluded from the cell spaces to be sensed by the distance sensor115.

More specifically, the environment change unit 202 executes the controlprogram for transporting and disposing the shielding materials 650 toshield the specific cell space with the shielding material 650. FIG. 6is an external perspective view of the environment arrangement robot 100that transports the shielding material 650.

The shielding material 650 is, for example, a rectangular parallelepipedcardboard and is held by the arm part 120. The arm part 120 assumes aposture in which a projection of the environment arrangement robot 100in the state of holding the shielding material 650 (a shadow cast on atraveling surface from a vertical direction) falls within a radius R.The environment change unit 202 searches for a path through which theprojection with the radius R can pass using the already createdenvironment map and transports the shielding material 650 from thepassage area 610 to the position where the specific cell space isshielded.

FIG. 7 is a diagram showing the target space in which the specific cellspace is shielded by the shielding materials 650. FIG. 7 is an overviewdiagram similar to FIG. 4. As shown in FIG. 7, when the inside of theglass door 613 is covered with the shielding materials 650, the mobilerobot that autonomously moves in the target area 600 will no longersense the glass door 613. That is, it can be said that the environmentarrangement robot 100 is arranging the environment of the target area600 for the mobile robot. When the environment arrangement robot 100covers the glass door 613 with the shielding materials 650, theenvironment arrangement robot 100 operates the distance sensor 115 toupdate each evaluation value given to the cell space near the glass door613.

FIG. 8 is a diagram for describing the environment map created after theenvironment is changed. The environment map shown in FIG. 8 isillustrated in a manner similar the environment map shown in FIG. 5. Itcan be seen that the surface material of the shielding materials 650 isa material that appropriately scatters the laser beam, and theevaluation values close to “1” are given to the cell spaces where theshielding materials 650 are disposed. The environment map created afterthe environment is changed does not include the cell spaces of“presence/absence of an object is unknown”. Thus, the mobile robot canestimate its own location more accurately when it receives such anenvironment map and refers to the environment map.

Here, as an example of the environment change unit 202 changing thesurrounding cell spaces so that the specific cell space will not besensed by the distance sensor 115, an example in which the specific cellspace is shielded by the shielding materials 650 has been described.However, the example of changing the surrounding cell spaces is notlimited to this. For example, existing furniture and fixtures may bemoved around the specific cell space.

Further, for example, an adhesive sheet for appropriately scattering thelaser beams may be prepared and attached to the surface of the glassdoor 613. When the attachment to the glass door 613 is successful, thespecific cell spaces corresponding to the glass door 613 can be changedto normal cell spaces having the evaluation values close to “1”. Thatis, the environment change unit 202 may change the specific cell spaceitself having the evaluation value close to “0.5” so that the evaluationvalue will become close to “1” or “0”, i.e., the probability of theevaluation value of the presence/absence of the object will becomelarger.

Next, a processing flow of the environment arrangement robot 100 will bedescribed. FIG. 9 shows the processing flow of the environmentarrangement robot. The flow starts from the time when the environmentarrangement robot 100 reaches a movement start point shown in FIG. 4.

First, in Step S101, the map creation unit 201 of the control unit 200creates the environment map as shown in FIG. 5. Specifically, as shownin FIG. 4, sensing is executed by the distance sensor 115 while thetarget space is searched, and the evaluation value of each cell space iscalculated from the measurement result. Then, the calculation of theevaluation value is continued until the environment arrangement robot100 returns to the movement start point, and the environment map istemporarily completed at the time when the environment arrangement robot100 returns to the movement start point.

In Step S102, the control unit 200 evaluates as to whether or not thespecific cell space is included in the created environment map.Specifically, as described above, when the evaluation value is givenwithin the range of 0 to 1, for example, the cell space having theevaluation value falling within the predetermined range of 0.35 orgreater and less than 0.65 is evaluated as the specific cell space. Whenit is determined that the specific cell space is not included in thecreated environment map, the process proceeds to Step S108, whereas whenit is determined that the specific cell space is included in the createdenvironment map, the process proceeds to Step S103.

In Step S103, the control unit 200 evaluates as to whether or not thecell space to be the target can be changed by the environment changeunit 202. More specifically, as described above, it is evaluates as towhether or not the state of the specific cell space itself can bechanged or the state of the cell space near the specific cell space canbe changed. When it is evaluated that neither one of the state of thespecific cell space and the state of the cell space near the specificspace can be changed, the process proceeds to Step S106. When it isevaluated that one of the state of the specific cell space and the stateof the cell space near the specific space can be changed, the processproceeds to Step S104.

In Step S104, the environment change unit 202 attempts to change thecell space to be the target. According to the example described withreference to FIG. 6, the shielding materials 650 are disposed in thecell space near the specific cell space to attempt to change thespecific cell space so that it will not be sensed by the distancesensor. Then, the process proceeds to Step S105 where it is evaluated asto whether or not the change has been successful. When it is evaluatedthat the attempt for the change has failed, the process proceeds to StepS106, whereas when it is evaluated that the attempt for the change hasbeen successful, the process proceeds to Step S107.

In Step S106, the control unit 200 notifies the user via thenotification unit 260 that the cell space to be the target cannot bechanged or that the cell space to be the target has failed to bechanged. When the notification unit 260 includes a display unit, thestate of the cell space to be the target may be captured by the cameras114 and the image may be displayed on the display unit. The user maychange the cell space to be the target by, for example, attaching anadhesive sheet on the glass door by himself/herself.

In Step S107, the map creation unit 201 performs the sensing by thedistance sensor 115 again on the cell space to be the target andrecalculates the evaluation value. Then, the map creation unit 201updates the environment map to the latest environment map.

The control unit 200 transmits the environment map created by the mapcreation unit 201 to the mobile robot that will execute the task in thetarget area 600 later on via the transmission unit 250. When thetransmission of the environment map is completed, a series of processingis ended.

In the embodiment described above, the map creation unit 201 continuesto create the environment map until the environment arrangement robot100 starts from the movement start point and then returns to near thespecific cell space and changes the cell space to be the target. Asdescribed above, when the environment map is continuously created untila predetermined condition is satisfied, for example, it is possible tomeasure the same cell space several times and thereby to reduce theinfluence of a moving object accidentally present such as an operator onthe evaluation value. In this case, the predetermined condition may be,in addition to the condition specifying the time from start to return,the conditions such as performing the sensing a plurality of times atintervals of a certain period of time and continuing the sensing for aspecified period of time.

In the embodiment described above, a rider is employed as the distancesensor 115. However, the distance sensor 115 may not be a rider. As longas it is a distance sensor capable of measuring the distance to thetarget, it may be an ultrasonic sensor, a distance image sensor, or thelike. Alternatively, the distance sensor may not be a single distancesensor having a scanning mechanism and it may instead be, for example, adistance sensor array in which the sensors are oriented in directionsdifferent from one another.

In the above embodiment, the environment map having the target space asone layer of the horizontal cross section is created. Alternatively, anenvironment map defined by three-dimensionally divided cell spaces maybe created. When the environment map is used for estimating a locationof the mobile robot, unlike the environment map for avoiding obstacles,the environment map of one layer of the horizontal cross section issufficient for that purpose. However, when the three-dimensionalenvironment map can be used in this case, the accuracy of theself-location estimation can be improved. Moreover, thethree-dimensional environment map can be conveniently used for avoidingobstacles. Note that when the three-dimensional environment map is to becreated, a distance sensor capable of scanning also in the heightdirection may be employed or a plurality of distance sensors may bedisposed in the height direction.

The control program can be stored and provided to a computer using anytype of non-transitory computer readable media. Non-transitory computerreadable media include any type of tangible storage media. Examples ofnon-transitory computer readable media include magnetic storage media(such as floppy disks, magnetic tapes, hard disk drives, etc.), opticalmagnetic storage media (e.g. magneto-optical disks), CD-ROM (compactdisc read only memory), CD-R (compact disc recordable), CD-R/W (compactdisc rewritable), and semiconductor memories (such as mask ROM, PROM(programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random accessmemory), etc.). The program may be provided to a computer using any typeof transitory computer readable media. Examples of transitory computerreadable media include electric signals, optical signals, andelectromagnetic waves. Transitory computer readable media can providethe program to a computer via a wired communication line (e.g. electricwires, and optical fibers) or a wireless communication line.

From the present disclosure thus described, it will be obvious that theembodiments of the present disclosure may be varied in many ways. Suchvariations are not to be regarded as a departure from the spirit andscope of the present disclosure, and all such modifications as would beobvious to one skilled in the art are intended for inclusion within thescope of the following claims.

What is claimed is:
 1. An environment arrangement robot for arranging anenvironment of a target space in which a mobile robot autonomouslymoves, the environment arrangement robot comprising: a movementmechanism for autonomous movement; a distance sensor configured tomeasure a distance to an object present nearby; a map creation unitconfigured to divide the target space into a plurality of cell spacesand provide an evaluation value to each of the cell spaces based on aresult of the measurement of the distance sensor obtained while theenvironment arrangement robot autonomously moves in the target space tothereby create an environment map of the target space, the evaluationvalue indicating a probability of whether or not there is an object inthe corresponding cell space; and an environment change unit configuredto change, among the plurality of cell spaces, a specific cell spacehaving the evaluation value within a range evaluated that theprobability of whether or not there is an object in the specific cellspace is low in such a way that the probability that the object ispresent will become greater or change a surrounding cell space in such away that the specific cell space will be excluded from the measurementby the distance sensor.
 2. The environment arrangement robot accordingto claim 1, wherein the map creation unit updates the evaluation valueof the specific cell space and the evaluation value of a cell space nearthe specific cell space changed by the environment change unit based ona remeasurement result of the distance sensor.
 3. The environmentarrangement robot according to claim 1, further comprising atransmission unit configured to transmit the environment map created bythe map creation unit to the mobile robot.
 4. The environmentarrangement robot according to claim 1, wherein the environment map is amap of one horizontal cross section of the target space.
 5. Theenvironment arrangement robot according to claim 1, wherein theenvironment change unit attempts to attach a predetermined attachingobject to the specific cell space.
 6. The environment arrangement robotaccording to claim 1, wherein the environment change unit attempts todispose materials for shielding the specific cell space.
 7. Theenvironment arrangement robot according to claim 1, further comprising anotification unit configured to notify, when the change of the cellspace targeted by the environment change unit fails, a user of thefailure.
 8. The environment arrangement robot according to claim 1,further comprising a notification unit configured to notify, when thecell space targeted by the environment change unit cannot be changed, auser that the cell space targeted by the environment change unit cannotbe changed.
 9. The environment arrangement robot according to claim 1,wherein after the map creation unit creates the environment map until apredetermined condition is satisfied, the environment arrangement robotmoves to near the specific cell space, and the environment change unitexecutes the change of the cell space to be the target.
 10. Anon-transitory computer readable medium storing a control program of anenvironment arrangement robot for arranging an environment of a targetspace in which a mobile robot autonomously moves, the control programcausing a computer to execute: measuring, by a distance sensor, adistance to an object present nearby while operating a movementmechanism and the environment arrangement robot autonomously moves inthe target space; dividing the target space into a plurality of cellspaces and providing an evaluation value to each of the cell spacesbased on a result of the measurement of the distance sensor obtained inthe measuring to thereby create an environment map of the target space,the evaluation value indicating a probability of whether or not there isan object in the corresponding cell space; and changing, among theplurality of cell spaces, a specific cell space having the evaluationvalue within a range evaluated that the probability of whether or notthere is an object in the specific cell space is low in such a way thatthe probability that the object is present will become greater or changea surrounding cell space in such a way that the specific cell space willbe excluded from the measurement by the distance sensor.